The wheel brakes of an aircraft are controlled by the pilot after landing to assist in the ground deceleration of the aircraft. The wheel brakes can also be controlled by the pilot (or by a member of the ground crew) during ground taxi maneuvers. The large mass of an aircraft and the high landing speed results in very high momentum, which can translate to very high dynamic loads during braking maneuvers (especially when the brakes are applied suddenly). Consequently, aircraft landing gear are designed to withstand braking loads that are generated in response to the application of the aircraft wheel brakes. This design objective results in heavy and bulky landing gear assemblies.
Hydraulic-based aircraft brake systems may employ techniques intended to alleviate landing gear loads caused by brake actuation. Once such technique switches between fore and aft wheel brakes on a landing gear, while regulating the onset timing of the fore/aft wheel brakes. Although this system results in less lurching of the aircraft during braking, the load alleviation scheme is not based upon current operating conditions of the aircraft, such as the aircraft speed or the rate of brake pedal deflection. Another load alleviation scheme limits the amount of hydraulic fluid and/or the flow rate of hydraulic fluid in a hydraulic brake system. This is a simple mechanical scheme that restricts the brake torque output for all braking and operating conditions. This scheme is always active and it is not based upon current operating conditions of the aircraft, such as the aircraft speed or the rate of brake pedal deflection.